For the logging on of a portable part at a so-called DECT (Digital Enhanced Cordless Telecommunications) base station which is capable of simultaneously controlling more than only one single associated portable part, the base station must be placed into a log-on mode. During the log-on mode, which is switched on for only a limited period for safety reasons, the base station is capable of accepting measures for logging on a portable part and of accepting the log-on of the portable part.
Today, base stations are known, for example by Hagenuk, which switch to the log-on mode when a supply voltage for the base station is newly applied or the supply voltage is applied again to the base station after previous elimination of the supply voltage.
This method makes it possible to manufacture base stations without a separate key especially for switching on the log-on mode.
The disadvantageous factor in such a method for logging on portable parts at a base station is that, in principle, it is possible to produce a short-time failure of the supply voltage of the base station without access to the area in which the base station is set up, and then to log on an outside portable part remote from the base station at the base station during the period of the log-on mode.
In this manner, it would be possible to telephone at someone else's cost. The failure of the supply voltage of the base station could be produced illegally by operating the corresponding fuses for a short time; for example, in the case of rented apartments with a fuse box mounted in the common stairwell.
Starting with a method or a base station of the type initially mentioned, it is an object of the present invention to improve the method or the base station, respectively, in such a manner that an unintended or improper log-on of an outside portable part at a base station is prevented.